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Initial Results from the Variable Intensity Sonic Boom Propagation DatabaseAn extensive sonic boom propagation database with low- to normal-intensity booms (overpressures of 0.08 lbf/sq ft to 2.20 lbf/sq ft) was collected for propagation code validation, and initial results and flight research techniques are presented. Several arrays of microphones were used, including a 10 m tall tower to measure shock wave directionality and the effect of height above ground on acoustic level. A sailplane was employed to measure sonic booms above and within the atmospheric turbulent boundary layer, and the sailplane was positioned to intercept the shock waves between the supersonic airplane and the ground sensors. Sailplane and ground-level sonic boom recordings were used to generate atmospheric turbulence filter functions showing excellent agreement with ground measurements. The sonic boom prediction software PCBoom4 was employed as a preflight planning tool using preflight weather data. The measured data of shock wave directionality, arrival time, and overpressure gave excellent agreement with the PCBoom4-calculated results using the measured aircraft and atmospheric data as inputs. C-weighted acoustic levels generally decreased with increasing height above the ground. A-weighted and perceived levels usually were at a minimum for a height where the elevated microphone pressure rise time history was the straightest, which is a result of incident and ground-reflected shock waves interacting.
Document ID
20080017418
Acquisition Source
Armstrong Flight Research Center
Document Type
Conference Paper
Authors
Haering, Edward A., Jr. (NASA Dryden Flight Research Center Edwards, CA, United States)
Cliatt, Larry J., II (NASA Dryden Flight Research Center Edwards, CA, United States)
Bunce, Thomas J. (NASA Dryden Flight Research Center Edwards, CA, United States)
Gabrielson, Thomas B. (Pennsylvania State Univ. University Park, PA, United States)
Sparrow, Victor W. (Pennsylvania State Univ. University Park, PA, United States)
Locey, Lance L. (Pennsylvania State Univ. University Park, PA, United States)
Date Acquired
August 24, 2013
Publication Date
May 5, 2008
Subject Category
Acoustics
Meeting Information
Meeting: 14th AIAA/CEAS Aeroacoustics Conference
Location: Vancouver, BC
Country: Canada
Start Date: May 5, 2008
End Date: May 8, 2008
Sponsors: American Inst. of Aeronautics and Astronautics, Confederation of European Aerospace Societies
Distribution Limits
Public
Copyright
Public Use Permitted.

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